The two blocks are placed on inclined surface with the cable taut. Determine the force P required to initiate motion of the 15 kg block if (P) applied down the incline ? H= 0.40 8 kg H= 0.30 15 kg 20°

A rectangular painting measures 1.00 m tall and 1.50 m wide, Fig. a. It is hung on the side wall of a spaceship which is moving past the Earth at a speed of 0.90c. (a) What are the dimensions of the picture according to the captain of the spaceship? (b) What are thedimensions as seen by an observer on the Earth? (L=L0*√1 − (?)2 )

. A 25kg wooden plate is held in place by two strings attached to the ceiling and the wall. The string attached to the ceiling makes an angle 40° with the horizontal and the string attached to the wall makes 90° with the wall. Determine the force in each string.

A particular bridge, with a length L, consists of a horizontal slab with a weight of 50.0 kN, with the weight uniformly distributed. The slab is held up by one support 20% of the way across the bridge, and a second support 80% of the way across the bridge. As shown in the picture, a truck with a weight of mg = 12.0 kN is driving from left to right across the bridge. 0.4L horizontal slab mg| 0.2L 0.2L (a) Once the truck is completely off the bridge, how much force will the left support exert on the horizontal slab? We're looking for an answer in kilonewtons (kN), which is what values are given in above. kN (b) When the truck is at the position shown, where its full weight can be taken to act at a point 40% of the way across the bridge, calculate the force that each support exerts on the horizontal slab. We're looking for two answers-the value of each of the support forces. The force exerted by the left support is kN. The force exerted by the right support is kN. (c) As the truck…

3. The force F required to move a box by pulling on an attached rope that forms an angle w with the horizontal is given by fmg F(w) = cOSw + f sin w where f, m, g > 0 are all constant. (a) Show that the angle wo that minimizes the required force to set the box in motion is given by arctan(f) (b) Show that this minimal force F(wo) is proportional to (a constant multiple of)

A uniform plank of length 2.00 m and mass 31.5 kg is supported by three ropes, as indicated by the blue vectors in the figure below. Find the tension in each rope when a 715–N person is d = 0.500 m from the left end. magnitude of  T1       N magnitude of  T2       N magnitude of  T3       N

A 10.0 kg mass is at rest on a board inclined at an angle of 30.0o above the horizontal. The mass is held in place by the combination of static friction and the 10.6 N tension in a cord attached to the mass on the uphill side, and running parallel to the board. Find the coefficient of static friction (s) between the mass and the board.

A fence post of mass m = 8 kg supports a fence with three lengths of barbed wire. The bottom wire is a distance d = 0.35 m from the ground and each wire is a distance 0.35 m above the previous one. Each of these three wires has the tension on it. For this problem, assume that the force exerted by these wires is purely horizontal. An additional guy wire is used to keep the pole upright with a tension of Fa = 490 N. The guy wire attaches to the post at a point h = 0.86 m above the ground and makes an angle of θ = 45 with respect to the horizontal. Write an expression for the tension in any one of the three fence wires.  What is the normal force that the ground exerts upward on the post?